1. Field of the Invention
The present invention relates to a sheet for mounting a workpiece, and more particularly to a sheet for mounting a workpiece that has holes or grooves on a surface thereof.
2. Description of the Related Art
Polishing generally refers to control of abrasion of an originally rough surface in a chemical mechanical polishing (CMP) process, in which slurry with fine particles is evenly distributed on a top surface of a polishing pad and meanwhile a workpiece is pressed against the polishing pad to repeat abrasing regularly. The workpiece is an object such as a semiconductor, a storage medium workpiece, an integrated circuit, a liquid crystal display (LCD) flat glass, an optical glass, and a photovoltaic panel. During polishing, a sheet for mounting a workpiece is needed for carrying and retaining the workpiece, and the quality of the sheet for mounting the workpiece directly influences the polishing effect of the workpiece.
FIG. 1 is a schematic view of a polishing device using a conventional sheet for mounting a workpiece disclosed in U.S. Pat. No. 5,871,393. The polishing device 1 includes a lower base plate 11, a sheet 12, a workpiece 13, an upper base plate 14, a polishing pad 15, and slurry 16. The lower base plate 11 is relative to the upper base plate 14. A bottom surface 122 of the sheet for mounting the workpiece 12 is adhered to the lower base plate 11 by a self-adhesive layer 17, and a top surface 121 of the sheet 12 is used for carrying and retaining the workpiece 13. The polishing pad 15 is retained on the upper base plate 14 and faces the lower base plate 11, for proceeding polishing on the workpiece 13.
The operations of polishing device 1 are described as follows. Firstly, the workpiece 13 is disposed at the sheet 12, and the workpiece 13 is sucked by the sheet 12. Then, the upper base plate 14 and the lower base plate 11 rotate in opposite directions and meanwhile the upper base plate 14 moves downwards to enable the polishing pad 15 to contact a surface of the workpiece 13. The continuous refill of the slurry 16 and the function of the polishing pad 15 may realize the polishing of the workpiece 13.
Although the sheet 12 is capable of mounting the workpiece 13, after the polishing is completed, it takes a long time for taking off the workpiece 13 from the sheet 12. Particularly, nowadays, the workpiece 13 is developed to have a large size and a thin thickness, it becomes more difficult to take off the workpiece 13, and thus the working efficiency is reduced and the breakage rate is increased.
Therefore, it is in need of an innovative and inventive sheet for mounting a workpiece to solve the above-mentioned problems.